1. Field of the Invention
This invention relates to apparatus and method for printing portable document format (PDF) files, and in particular, it relates to printing portable document format (PDF) files that contain corrupted pages.
2. Description of Related Art
PDF file format is widely used in document processing applications and printing processes. A PDF file contains complete description of a fixed-layout flat document that includes text, fonts, graphics and other information needed for displaying and printing the document. A PDF file often contains multiple pages each can be individually displayed or printed. However, oftentimes some of the pages in a PDF file are corrupted so that they cannot be displayed or printed correctly.
When a PDF file containing corrupted pages is printed, most current Printer Description Language (PDL) applications and printer drivers/interpreters will process the print job as a whole document, and will stop the process when an error such as a corrupted page is encountered. In addition, even when a page range is specified in an application print dialog, the application usually still process the job as a whole document before extracting the specified pages for printing. As result, the application still terminate the process if an error is encountered and not to print the document. Moreover, with a direct print method that does not go through a print application or printer driver, the PDL still behaves similarly by terminating the rendering process, and will generates an error message, due to the failure of rendering the whole document.
However, in a corrupted PDF file, many times there are still some pages within the document that are correctly formatted and may contain important info for users who wish to print them. That is, for certain users it is important to able to print the non-corrupt data because it might contain important information to the users and it also provides useful information about the corruption of the file, such as at what page(s) the corrupted data has occurred. Therefore it is desirable to print out the non-corrupted pages of a document contained in a PDF file even when some other pages of the document are corrupted.
In addition, it is also desirable to provide the users an opportunity to view the error information when page corruption is encountered, so that the users may correct the problem or cure the corruption, so that these pages may be printed correctly. Nonetheless, when the corrected PDF file is resent to be printed, it is desirable to print the corrected pages only without reprint the already-printed non-corrupt pages to avoid the waste of paper and other resources.
It is desirable to provide a new method for printing PDF files that contain corrupted pages to address the problems discussed above with regard to the behaviors and drawbacks of current PDF processing/printing applications and printer driver/interpreters.